In June the FBI conducted about 2.1 million background checks on people attempting to purchase firearms, according to the National Instant Criminal Background Check System (NICS). That’s a 40% increase from June of last year when about 1.5 million background checks were conducted.

At this time last year, there had been about 10.5 million background checks. So far in 2016 there have already been 13.8 million, about a 32% increase. 2015 was a record-breaking year for gun sales with 23.1 million background checks and, with every month so far in 2016 breaking records, we’re on track to beat that this year.

NICS doesn’t reflect the exact number of firearms sold in the U.S.—it doesn’t account for people purchasing multiple guns at one time, gun sales that don’t involve a federally licensed dealer, or buyers who don’t pass background checks. However it does reflect trends in gun sales, and background checks tend to increase following gun-related tragedies.

June saw the worst mass shooting in U.S. history at the Pulse nightclub in Orlando, leaving 49 victims dead and more than 50 injured. Events like these generally contribute to increased gun sales for two likely reasons: people are scared and want to defend themselves, and that’s when politicians reignite the gun control debate. This explains the 40% year-over-year increase in gun sales in June, as well as in the first two months of this year following the San Bernardino shooting in December.